Circuit breaker



Jan. 29, 1935. L. c. REED 1,989,497

CIRCUIT BREAKER Filed March 20, 1930 2 Sheets-Sheet 1 Jan. 29, 1935.

v5727 275 l Z 54 fr f4 da 5 ZN VEN To R y/hdr; C Feed TTQRNEY Patented`Jan. 29,' 1935 r v Y i I UNITED sTATEs PATENT OFFICE CIRCUIT BREAKERLyman C. Reed, New Orleans, La., assigner, by mesne assignments, toI-T-E Circuit Breaker Company, Philadelphia, Pa., a corporation of NewJersey Application March 20, 1930, Serial No. 437,513 23 Claims. (Cl.20D-89) This invention relates generally'to apparatus trical apparatusof the so-called panel-board for interrupting and protecting electricalcirtype; and to improve and simplify the construccuits or systems and,more particularly, to a certion of circuit-breakers generally.

tain new and useful improvement in such appa- And with the above andother objects in View, ratus of the type commonly known as circuitmyinvention resides in the novel features of 5 breakers, form,construction, arrangement, and combina- Heretofore, so far as I amaware, circuittion of parts hereinafter described and pointed breakersemployed for the purpose of protecting out in the claims. electricalsystems against so-called overload and In the accompanylg drawings (2Sheets)- short-circuit conditions have been actuated on Figure 1 is aside elevational view of a circuit- 10 release of a spring-operatedmechanism which breaking apparatus embodying my invention, has a fixedtime-interval of circuit-opening re- Shown in circuit-closing position,intermediate sponse to such overload or short-circuit condipositions ofslome of the members being shown tion, such time-interval beingdependent wholly by dot-dash lines, one of the side walls of the l5 uponthe action of spring pressure operating on housing being omitted and thetop Wall thereof 15 associated fixed weights. In such cases, the nowbeing shown in section;

of short-circuit current very often attains a mag- Figure 2 is aplanview of the apparatus, the nitude approximately equal to thecapacity of top wall of the housing being removed; the system in whichthe short occurs, and fre- Figure 3 iS a Sectional VBW hrOugh theappaquently causes the destruction of the circuitratus takenapproximately along the line 3 3, 20

breaker or some part of it before the current- Figure 1; now in thecircuit is ruptured. The lost time Figure 4 is a view similar to Figure1, the apoccasioned by such fixed time-interval of rupparatus, however,being shown in circuit-openture of the circuit is exceedingly importanton ing DOSitOn aS When the Circuit-breaker is autooverloads of themagnitude of short-circuits, not matically actuated or tripped as on anoverload 25' only because the heating of the separable conin thecircuit; and

tacts of the breaker is unnecessarily prolonged, Figure 5v is asectional view through the appabut because the short-circuit current hasthe opratus taken approximately along the line 5 5, portunity of growthto many times the magni- Figure 4.

tude it would have if interrupted in a time-inter- Referring now more indetail and by reference 30 val having a variable relation to thestrength of characters to the drawings, which illustrate a the initialcurrent ow caused by the shortpreferred embodimentof my inventiontheworkcircuit. ing parts of the apparatus are for the most part My presentinvention has hence for its prinenclosed preferably by a housing A whichincipal object the provision of an efficient circuitcludes a top wall land separable side walls 2 35 breaking or interrupting apparatus forboth of suitable contour and constructed preferably A. C. and D. C.systems adapted for the solution of any suitable insulation material.Fixed beof the various problems stated above and the tween the sideWalls 2 to form one end wall of accomplishment in approximateiy thelowest the housing A, is an insulation block 3 having possible time ofthe results sought; and in addisubstantially an inverted L shape, theinturned 40 tion, the provision of means for protecting such horizontalleg 4 thereof being spaced from the electrical systems against simpleoverloads while top wall l and extending somewhat more than permittingmomentary heavy or so-cailed starthalf the length thereof. Also fixedbetween the ing overloads current-flow to pass through, vside walls 2 atthe other end of the housing, is a without tripping, thecircuit-breaker; to prosubstantially L-shaped block 5 of insulation ma-45 vide a circuit-breaker arranged for calibration terial, its bottomleg forming a portion of the in a manner to distinguish between simpleoverbottom wall of the housing, and its upstanding loads andshort-circuit overloads; to provide leg 6 being spaced from the opposingside walls such protection in an automatic manner irre- 2 andterminating approximately halfway the spective of deliberative actiontaken for closing height thereof. 50

the circuit-breaker against abnormal current- The circuit-breaker properincludes a fixed now; to substantially abate the growth of arc terminalmember l secured to and upon the top at the separating contacts of thecircuit-breaker; of the inner end of the insulation block 4 by a toprovide an automatic circuit-breaker adapted suitable fastening element8. 'I'he terminal 'I 5 especially, though not exclusively, for use inelechas a part depending over the end of the mem- 55 ber 4 to form astationary'conducting pole ory contact 9a. Co-operating with the pole9a, is a separably engaging conducting pole or contact 9 adapted foractuation into and out of engagement with the contact 9a forrespectively closing and opening the circuit. -The contact or pole 9 isembracingly carried by, and secured with a suitable lfastening element10 in the bight of, an inverted substantially U-shaped swingablyactuable contact-carrier 11.

'I'he depending legs of the member 11 terminate in oppositelypresented'axially aligned ears or pivot members 12 edgewise presentedfor disposition in and rockably engaging aligned grooves 13 formed inthe forked ends 14 of a horizontally 'disposed conducting-terminal 15suitably xed on the upper end of the member 6 with its other endprojecting outwardly therebeyond, for purposes soon appearing.Transversely threaded through the lower end of the block 6 into a recessi8 formed for the purpose in the member 5, is an adjusting pin or screwl7 movable in the plane of swinging actuation of the holder l1oppositely of the pivotal axis thereof. Pivotally secured at an end tothe pin 17, is an elongated coiled spring or tensionally yieldablemember 18 having its other end stretched past the pivotal axis of theholder 11 and attached intermediate its legs to a pin 19 disposedtransversely therethrough, as best seen in Figure 3.

It may be here stated that the spring 18 is caused, on swingableactuation of the contactcarrier 11, to take a position alternately onopposite sides of the pivotal axis thereof. So arranged, the spring 18and the swingable carrier 1l co-operatively constitute a toggle which,when knuckled in one direction, acts to engage the carried contact 9with the fixed contact 9a in circuit-closing position. However, when thetoggle is knuckled in the opposite direction, the spring 18 acts. withincreasing force to separate and acceleratingly widely space thecontacts 9 and 9a in circuit-opening'actuation. This wide spacing of thecontacts 9, 9a, is accomplished with such a high resulting velocity andin such a short interval of time as to rupture the current-flowsubstantially and abate the occurring arc before the same can grow toappreciable magnitude.

By manipulating the screw 1'7, the pivoted end of the spring 18 may beshifted relatively to the pivotal axis of the member 11 to regulate thecontact pressure between the poles 9 and 9a and' consequently the forceor eiort required to be exerted on the member 1l for knuckling thetoggle into circuit-opening position.

The automatic tripping mechanism includes an electromagnet B preferablycomprising a pair of windings 20 mounted on van inverted substantially.U-shaped core 21 of suitable material, the yoke thereof being sunk intothe lower face of the member 4 and therein secured by fastening elements22, the depending legs of the core 21 termi` nating in preferablyhorizontally aligned magnetic-poles l23. Electro-magnetically associatedwith the windings 20, is a swingable so-called overload-armature 24having an end pivotally supported in a suitable recess in the wall 3 ona pin25 iixed therein, for actuation of its other end toward and awayfrom the poles 23. lSecured between a lug 26 depending from the armature24 and an adjusting screw .27 threaded through the wall 3, is acalibrating spring or tensional member 28 adapted, by suitableregulation of the 'screw 27, to tensionally weight the armature 24 foryieldingly opposing tl"e response thereof toand at less than apredetermined or normal current flow through the windings 20.

At its s'wingable end, the armature 24,;carries an endwise presented lug29 normally spaced from butv adapted, on upward actuation of saidarmature, to impinge, a pimficglaterally presented for such purpose fromthe swingable end of another or short-circuit-armature 30 alsoelectromagnetically associated with the windings 20, 20, and pivotallysupported on the pin 25 for swingable actuation alongside of thearmature 24. The armature 30 is provided at its swingableend with anendwise presented lug 31 substantially touching for disengageablyimpinging an end of a strikerlink 32 depending from a pin 33 laterallyspaced from the pivotal axis of the contact-holder ll and secured to andbetween the legs thereof.

The depending end ofthe link 32 and the cooperating swingable end of thearmature 30 work in the recess 16 which is suitably open at an end forsuch purpose.

The response of the armature 30 to current flow in the windings 20 isopposed by the force of the spring 18, which is brought into action onlifting impingement of the lug 3l with the link 32. As has beendescribed, this force of the spring 18 .may be varied, and in suchrespect the spring 18 may be arranged to yield or calibrated, as may besaid, for circuit-opening actuation of the member l1 on response of thearmature 30 to and at more than a predetermined or abnormal current flowthrough the windings 20, said abnormal current flow being selected inview of the maximum or short-circuit capacity of the system beingprotected. In magnitude between this maximum overload or short-circuitedcurrent-now and the said normal current-ow is a minimum over-loadcurrent-how, and for accordingly protecting the` system, the armature 24responds to current flow greater than that predetermined by itscalibration by advancing on the poles 23 with an increasing momentumsubstantially impartedas a sharp blow or kick to the armature 30y onimpingement of the lug 29 'with the pin Y 29a, as shown by dot-dashlines in Figure 1. Such momentum.is additive to the pull of the windings20 on the armatures 24 and 30 and more especially augmented by rea'sonof the relatively small air gap then existing between the poles 23 andthe armature 24. Together these several forces suce to open the circuitwith extreme rapidity, the armature 24 being most effective forovercoming the inertia of the moving parts of the circuit-breaker'beforecoming to rest against the poles 23.

The armature, however, is capable of a more extensive. circuit-openingmovement accommodating that required for swinging the contactmember 1lpast and beyond the dead-center'of toggle of which it forms a partfthespeed of the last portion of such movement being progressively increasedby reason of the increasing force with which the windings 20 act on thearmature 30 as it approaches the polesv 23, additive to the increasingforce'with which the .spring 18 acts on the swingable member 1l, thefinal circuitopening position being shown in Figure 4, and

being obtained after the armature 30 strikes the pole-pieces 23 by .theforce Aof the spring 18 conjointly with `the momentum ofthe moving partsacquired during the initial circuit-opening actuation thereof.`

On bverloads, armature 24 coacts with armature 30 to open the circuit,but on short-circuits armature 30` acts substantially alone, thusproviding independent and non-interfering protective agencies againstoverload and short-circuit conditions, for upon occurrence of ashort-circuit, the flow of current is such that armatures 24 and 30 areattracted simultaneously by windings 20, 20, hence the lug 31substantially touching the striker 32, the armature 30 acts at once toopen the circuit. The rise of flux in the magnetic circuit ofthe-windings 20 is in phase with the rise of current therein, hence themagnetic circuit reaches its saturation point in less time under heavyshort-circuit conditions than under light ones, and the armature 30 isactuated sooner under the first condition than under the second. Thearmature 30 is set to open the circuit at a point substantially belowsaturation of its magnetic circuit, and its actuation being directlyresponsive to the growth of current and the capacity of the protectedsystem, the circuit-rupturing time-interval of all the automaticcircuit-rupturing parts of the breaker is inversely proportional to thegrowth of short-circuit current flow. As a result, excessive growth ofcurrent in the protected system and consequent destructivearcing at thepoles of the breaker is avoided.

The apparatus Y also includes a manually .manipulative actuatingmechanism for closing the circuit-breaker, kwhich comprises means forrendering the tripping means trip-free or operable independently of theactuating means. For such purpose, one of the depending legs of theholder 11 is provided with a substantially rhomboidal aperture 34, itsfront wall 35 being inclined from the rear wall 35 so that the aperture34 is wider at its top wall 36 than at its bottom wall 36. Provided atits forward end with a finger or detent 37 laterally presented ,in theaperture 34l for alternately impinging the several walls thereof, is ashiftable latch-lever 38 pivoted at its rear end, as at 38a, on a leg ofa U-shaped swingably upstanding inverted substantially U-shaped lever39, the depending legs thereof embracing the member 6 for impingingopposed stops 39a formed inthe terminal 15 and being pivotally supportedon the laterally projecting ends of a pin 40 fixed through the member 6adjacent its lower end. On actuating the lever 39, the finger .37 shiftscorrespondingly in the aperture 34. The latch 38 is also swingable onthe lever 39 and urged thereto by a spring or tensional member 41 havingits opposite ends suitably engaging the latch and the lever,respectively. On forward swinging of the levr39 from off orcircuit-opening position to "on or circuit-closing position,corresponding to like positions of the member 11, their latch 38advancingly engages its nger 37 with the walls 35, 36', at their cornerand is frictionally held thereto by the opposition of the spring 18while so advancing, until the/toggle constituted. by the spring 18 andmember 11 is forwardly past its dead-center, from whence furthercontinuing movement is caused by breaking the toggle in that direction,the member 11 being thereby actuated to circuit-closing position withincreasing force, or, as may be said, the breaker is snapped closed.

Thereupon, the finger 37 is disengaged from the wall 35, as shown bydot-dash lines in Figure 1, the spring 41 swinging the latch 38 upwardlyuntil the finger 37 impinges the opposite corner of the aperture formedby the walls 35', 36, Figure 1, thereby rendering the member 1l tripfree of the lever 38.

On circuit-opening actuation of the circuitbreaker proper, the member 11moves independently of the latch 38 sumciently by reason of theclearance between the finger 37 and the corner of its walls 35, 36, tobreak the toggle in circuit-opening direction and thus snap the breakeropen for interrupting the circuit. A stop 42, preferably comprising aprotruding end of the pin 19, depressingly engages an edgewise presentedcamface 43 on the latch 38 for clamping or locking the finger 37 intoimpingement with the walls 35, 36', at their corner on completion of thecircuit-opening movement of the member 11 accomplished by the action ofthe spring 18, thereby restoring the lever 38 to'actuating position.'I'he final portion of such movement is imparted to the latch 38 forcorrespondingly returning the lever 39 to off position, Figure 4. Thusthere is an intermediate circuit-opening position to which the member 11may be tripped when the lever 39 is in its on position, suchintermediate position being obtained when attempting to close thecircuit-breaker against a continuing abnormal condition in the protectedcircuit. From its on position, however, the lever 39 may be manually orotherwise swung rearwardly, the finger 37 engaging the wall 36' foractuation of the member 11 in circuit-opening movement until the toggleis broken in that direction, when the spring 18 acts to complete themovement, as above described. For manual manipulation ofthecircuit-breaker, a handle 44 preferably of insulation material isendwise presented from the lever 39 for work- ;ing in a slot 44a in thetop wall 1, the handle 44 having a pair of oppositely'presentedlaterally arcuate wings 45, 46, bearing suitable insignia, as off andon, respectively, for usual presentation thereof through the unoccupiedportions of the slot 44a at corresponding positions of thehandle 44.

By reason of its compact arrangement, the apparatus is adaptedespecially, though not exclusively, for use in connection withpanel-board types of electrical switching apparatus, for which purposethe wall 1 may conveniently constitute apart of the panel of theswitch-board, each leg of the circuit being protected by the singlepoletype of circuit-breaker shown. 47 designates the usual bus-bar of such apanel-board assembly. The terminal 15 is endwise presented from thehousing of the apparatus and electrically connected to the bus 47 by asuitable fastening element 48. The current flows through the terminal 15and thence through the forked ends 14 to the pivot-members 12 rockablystanding in the grooves 13 for co-operation therewith in providing aflexible electrical connection having a yielding live contact betweenthe pivot member 12 and the walls of the groove 13 under pressure causedby the spring 18, the current conducting efficiency thereof being suchthat said parts operate at a lower temperature than that of the poles 9and 9a when the latter are engaged in circuit-closing position. Thecurrent ow is thus established directly through the member 11, the usualpig-tail being omitted and the spring 18 forming no part of theelectrical circuit and hence being free from any distortional heatingeffect. From the pole 9a, the current flows through the terminal 7 andthence by leads 49, 50, in series through the pair of windings 20, 20,to a terminal 51 secured to the member 4 by a suitable fastening element52 and having electrical connection with the protected system or circuitthrough a suitable lead 53. A tap 54 is provided intermediate the coils20 for use when it is desired to connect the same in parallel. v

An unloading time-delay shunt 55 is preferably connected between theterminals 7 and 51, being in'parallel with or across the windings 20,20. The shunt 55 is of some positive temperature coemcient substance andis adapted to function to substantially short-circuit the windings 20,20, at the beginning of current ow, but to direct an increasingproportion of the shunted current through the windings 20 as thetemperature of the shunt increases, so that the growth of current ow inth electromagnet 20 is delayed for a time inversely proportional to rateof growth of current how in the circuit, which arrangement constitutes avery successful time-delay device, whereby heavy overloads. as may occurwhen a motor is started or when type C lamps are thrown on the circuit,may be carried momentarily without tripping the breaker. However, onshort-circuit conditions, the ow oi current through the windings 20 issuicient to substantially instantaneously actuate the armature foropening the circuit-breaker. Hence, there is pro- A vided substantiallyinstantaneous protection against short-circuits, and time-delayedprotection against overload conditions. As a variable resistanceresponsive to rate of growth of current ilow in the circuit, the device55 provides a discharge resistance for absorbing the greater portion ofthe inductive discharge ofthe windings 20 occurring when thecircuit-breaker is opened on heavy overloads and short-circuits. Hence,further, the growth of arc at time of rupture is substantially abatedand pitt i the separable contact 9 and 9a substantially 'u i fn d.

In actual practice,A a circuit-breaker embodying my present inventionhas been subjected to some ve to sixhuhdred dead shorts with sustainedpotential across its terminals, the circuit-breaker o in every instanceand the electrical connections thereof functioning according to theirseveral intended purposes for the entire period. The manner in which thetoggle constituted by the spring 18 and member 11 operates to separatethe poles 9 and 9a with such high velocity as to substantiallyabate thegrowth of arc therebetween; the manner in which the springs 18 and '28may be calibrated, the former for dead-shorts and the latter foroverloads; the freedom of such springs from current-dow, which wouldotherwise aiect their calibration; the small air-gap 'and consequentstrong pull of the armature 24 under overload conditions for initiatingcircuitopening actuation of the breaker; the fact that the handle 43"hasonly' two operative positions, namely, oil and on", whether the'breakeris opened manually or automatically; the fact that der pressure ot thespring 18; the fact that the rupturing time-interval varies inversely asthe current flow; the tact that the breaker is actuated by powersupplied by the excess of the shortcircuit or overload current; theabsence of springs or weights for initial actuation of the breaker;

the manner in which heavy overloads may be momentarily carried, and theinductive discharge of the windings 20 provided for, by the variableshunt 55; all resulting in complete and adequate protection both to thesystem being protected and the breaker itself, are among the advantagesprovided by the co-operant instrumentalities of my invention.

The use of the aparatus having been set forth as the descriptionproceeded and its several advantages pointed out, it is to be understoodthat changes and modifications in the form, construction, arrangement,and combination of the various parts of the breaker may be made andsubstituted for those herein shown and described without departing fromthe nature and principle of my invention.

Having thus described my invention, what I claim and desire to secure byLetters Patent is:

1. An electric circuit interrupting apparatus comprising, incombination, a first contact-member, a toggle including a swingablesecond-contact member for movement into and out of engagement with thefirst contact-member for respectively closing and opening the circuit,and current flow responsive means including a pair of swingablearmatures for co-operably knuckling the toggle for shifting the secondcontact-member out of engagement with the rst contact-member to open thecircuit.

2. An electric circuit interrupting apparatus comprising, incombination, a frame, a iirstcontact-member, a toggle including apivoted carrier, a second contact-member carried by the carrier, aspring attached at one end to the frame and at its'other end to thecarrier adapted to act on opposite sides of the axis of the carrier forswingably actuating the same for carrying the second contact-member intoand out of yielding engagement with vthe iirst contact-member forrespectively closing and opening the circuit, a link pivotally dependingfrom the carrier, and current ow responsive means comprising .aswingable armature adapted for engagement with the link for knucklingthe toggle for shifting the second contact-member out of engagement withthe rst contact-member to open the circuit.

3. An electric circuit interrupting apparatus comprising, incombination, a rst contact-member, a second contact-member, toggle meansfor' swingably actuating the second contact-member into and out ofengagement with the iirst contactmember for respectively closing andopening the circuit, said toggle means including a fixed support, apivoted carrier for the second contactmember, and a spring attached atone end to the support and at its other end to the carrier adapted toact on' opposite sides of the axis of the carrier, and means forknuckling the toggle to circuit, an armature actuable in opposition tothe circuit closing force of the tensional member for r opening thecircuit, and a second armature actu' able for assisting the firstarmature in overcoming the circuit-closing force of the tensionalmember.

5. An electric circuit interrupting apparatus comprising, incombination, a. iirst contact-member,.a swingable secondcontact-member,means including a tensional member adapted to act for yieldinglyengaging the second contact-member with the iirst contact-member forclosing `the circuitand to act with opposite eii'ect l for opening thecircuit, an armature actuable in opposition to the circuit closing forceof the tensional member for opening the circuit, a second armatureactuable for assisting the iirst amature in overcoming thecircuit-closing force of the tensional member, and means for regulatingthe actuation o1' said second amature.

6. An electric circuit interrupting 'apparatus comprising,incombination, a rst contact-member, a second contact-member, togglemeans 'for actuating the second contact-member into and out ofengagement with the rst contact-member u for respectively closing andopening the circuit,

tripping means for the toggle including a pair of co-operatingarmatures, one armature being calibrated for actuation on short circuitoverloads, and the other armature being calibrated to assist theactuation of the nrst armature on simple overloads, and means forindependently calibrating the respective armatures.

7. An electric circuit interrupting apparatus comprising, incombination, a first contact-member, a second contact-member, means foractuating the second contact-member into and out of engagement with thefirst contact-member forrespectively closing and opening the circuit,and means for actuating the flrst means to open the circuit, said lastmeans including a pair of armatures respectively actuable at maximum andlesser values of current iiow, the latter armature being adapted toimpinge the other armature at less than maximum current flow for circuitopening actuation therewith.

8. In an electric circuit-interrupting apparatus, in combination, aiirst contact-member, a pivotally swingable recessed carrier, a secondcontact-member mounted on the carrier, and operating mechanism includingan element operatively engaging the wall of the carrier-recess forswingably actuating the carrier for positively carrying the secondcontact-member substantially into circuit-closing engagement with thefirst contact-member, and means for moving the element away fromoperative connection between said operating mechanism and said carrierrecess when the contact-members are in engaging relation.

9. In an electric circuit-interrupting apparatus, in combination, aiirst contact-member, a pivotally swingable recessed carrier, a secoLcontact-member mounted on the carrier, means including an elementoperatively engaging the wall of the carrier-recess for swingablyactuatthe carrier for positively carrying the second contact-membersubstantially into circuit-closengagement with the first contact-member,the element being biased to carrier trip free position when thecontact-members are in engaging relation, and means for restoring theelement inte actuating engagement with the carrier when the latter is incircuit-opening position.

1G. In an electric circuit-interrupting apparasus incombination, a rstcontact-member, a pivotally swingable recessed carrier, a. secondcontact-member mounted on the carrier, and means for swingably actuatingthe carrier for carrying the second contact-member into and out ofengagement with the rst contact-member, said means including an elementoperatively engaging the wall of the carrier-recess, and a shiftablehandle having pivoted connection with said element.

11. In an electric circuit-interrupting apparatus, in combination, l apivotally swingable recessed carrier, a second contact-member 'mountedon the carrier, and means for swingably actuating the carrier forcarrying the second contact-member into and out of engagement with therst contact-member, said meansincluding a lever operatively engaging thewallof the carrier-recess, and a shiftable handle having pivotedconnection with the lever, the lever being biased in carrier trip treeposition when the contact-members are -in circuitclosing engagement'.

12. In an electric circuit-interrupting apparatus, in combination, a apivotally swingable spring-pulled carrier, a second contact-membermounted on the carrier, and means for swingably snapping the carrier forcarrying the second contact-member into and `out of yielding engagementwith the first contact-member, said means including a lever operativelyengaging the carrier, and a shiftable handle having pivoted connectionwith the lever, the lever being biased in carrier trip free positionwhen the contact-members arein circuitclosing engagement.

13. An electric circuit interrupting apparatus comprising, ber, a secondcontact-member, an apertured swingable carrier for the secondcontact-member, means including a swingable latch engageable with acorner of said aperture for circuit closing actuation of the secondcontact-member and engageable with a diagonally opposite corner of saidaperture and trip free of the second contact member when the latter isin engagement with the iirst contact-member, and means for restoring thelatch into actuating engagement with the second contact-member when incircuit-opening position.

J4. In an electric circuit-interrupting apparatus, in combination,circuit-closing means including a contact-carrier shiftable into and outof circuit-closing position, said carrier having a recess,carrier-shifting mechanism including a handle shiftable from off to onposition, a lever operatively engageable with the wall of the carrierrecess and operated by and movable with respect to said handle forshifting the carrier to circuit-closing position, means for biasing thelever in carrier trip free position when the carrier is in circuitclosing position, and means for restoring the lever to engagement withthe wall of the carrier recess subsequent to initial circuit rupturingmovement of the carrier for restoring the handle to'oif position.

' 15. A trip-free circuit breaker comprising stationarycontact-structure, an arm carrying movable contact structure forengagement therewith, a xed pivotal support for saidarm, an overcenterspring for holding said contact structures in engagement, an overloadresponsive device for overpowering said spring to effect separation ofsaid contact structures against the holding force thereof, a manuallyoperable lever, a member resiliently mounted thereon and connected witha lost motion to said pivoted arm, to allow circuit-closing movement ofsaid movable contact structure initiated by said lever to be completedby over-center Amovement o f said spring and to permit automaticcircuit-opening movement of said movable contact structure to beeffected despite restraint of said lever.

16. A trip-free circuit breaker comprising stationary contact structure,a pivoted arm actuating movable contact structure for engagement a firstcontact-member,

in combination, a rst contact-memfirst contact-member,

6 therewith, an over-center spring for holding said contact structuresin engagement, a lever rocked manually -in opposite directions to eectovercenter movements of said spring for circuitopening andcircuit-closing movementsv of saidl movable contact structure, alost-motion con-4 nection between said lever and said pivoted arm toeiect trip-free circuit openingof said contact structures, and overloadresponsive means for voverpowering said spring to eilectcircuitopeningmovement of said movable contact structure.

1'7. A trip-free circuit breaker comprising a stationary contact, amovable contact, an overcenter spring adapted to snap said movablecontact toward and away from engagement with said stationary contactwhen moved across center, means manually operable to move said springacross center, load-responsive means controlling means eiective toovercome said spring to move said movable contact from circuit-closedposition, and a lost-motion connection between'said A manual means andsaidmovable contact for rendering operation of said movable contact bysaid controlling means independent of said manual means.

18. A trip-free circuit breaker comprising a pivoted arm, a movablecontact operated by said pivoted arm, a spring connected to saidpivotedarm. the line of action of said spring passing from one side to theother of the pivoted axis of said arm to give a snap action, and to biassaid arm to apply contact pressure when in closed circuit position,actuating means adapted to move'said pivoted arm to circuit-closingposition, means responsive to circuit conditions for controllingmeanscapable of overcoming said spring lto move said arm tocircuit-opening position, and a lost motion connection between saidactuating means and said pivotedarm for rendering operation of saidmovablev contact by said controlling means independent of said pivotedarm.

19.- A trip free circuit breaker comprising a stationary contact, an armmovable about a fixed pivot, a movable contact. carried thereby, aspring adapted -to snap said movable vContact into engagement with saidstationaryvcontact and to maintain said contacts in engagement, meansmanually operable to cause said spring to snap said contacts intoengagement, and inverse time delay current-responsive means controllingmeans tovoverpower said spring and drive said movable arm toward opencircuit position and lost-motion means interconnecting said movable armand said manually operable means for rendering said movable armincapable'of lrestraining the contacts in closed circuit position.

2 0. A trip free panel board circuit breaker comprising a Iixed contact,a movable contact, a spring, for moving'said movable contact with a snapaction and for-holding said contacts in engagement; load-responsivemeans controllingy means eiective to overcome said spring and to drivesaid movable contact toward open-circuit position,v an enclosure forsaid contacts,- said spring, and said load-responsive means,'and a leverfor manually controlling said contacts pivoted within said enclosure andextending through a slot therein, and a lost-motion connection betweensaid lever and said movable contact whereby restraint .of said lever inclosed circuit position is incapable of restraining said contacts inclosed circuit position.

2l. A trip-free circuit breaker comprising cooperating stationary andmovable. contact structures, a pivotally mounted arm controlling saidmovable contact structure to effect engagement and disengagement of saidcontact structures, an overcenter spring connected to bias said arm tocircuit-opening or circuit-closing position, a

manually operable lever movable to eiect over-...v7.1-Y

center movements of said spring for -circuitopening and circuit-closingmovements of said movable contact structure, the relationship of partsbeing such that circuit-opening movement of said movablecontactstructure may be initiated independent of said manually operablelever, and electro-responsively controlled means for overpowering saidspring to eiect circuit opening movement of said movable contactstructure.

22. A trip-free circuit breaker comprising cooperating stationary andmovable contact structures, a pivotally mounted 'arm controlling saidmovable contact structure to effect engagement and disengagement of saidcontact structures, an overcenter spring connected to bias said arm tocircuit-opening or circuit-closing position, a manually operable levermovable to effect overcenter movements of said spring for circuitopeningand circuit-closing movements vof said movable contact structure, therelationship of parts being such that circuit-opening movement of saidmovable contact structure may be eiected independent of said manuallyoperable lever, and electro-responsively controlled means actingdirectly on said contact arm to overpower said spring and effect circuitopening movement of said movable contact structure.

23. A trip-free circuit breaker comprising cooperating stationary andmovable butt contacts,

a pivotally mounted arm controlling said movable contact to eiectengagement and disengagement of said contacts, an overcenter springconnected to bias said arm to circuit opening or circuit-closingposition whereby the contact pressure is dependent upon the deflectionof said spring from its neutral position, a manual control leveroperable to eiect overcenter movements of said spring Aforcircuit-opening and circuitclosing movements of said movable contactstructure, said movable contact being operable to circuit-openingposition irrespective of the retention of s aid lever in circuit-closedposition, and electroresponsively controlled means acting directly uponsaid contact arm to overpower said spring and effect circuit-openingmovement of said movable contact structure. y

LYMAN C. REED.

